Ranthambore digesters

What with the BAD 24 hours, and the excitement of the tiger, I forgot about this bit – the reason I came to Ranthambore instead of the Corbett Park; the reason I’m here in India. Well you didn’t think I was here to have a good time did you? This is jolly hard work I’ll have you know.
The Rajasthan countryside is parched and dry, with a bleak rugged beauty. The surrounding hills are pink and rocky, and from them comes much of the marble prevalent in shops and hotels, and which adorns the ancient buildings. The villages are a mixture of thatched mud houses and dwellings made of woven panels – I think they’re banana leaves - again with thatched roofs. These panels are sometimes used to enclose straw stacks or grain. Everywhere there are piles of cowpat, dried in the sun. These are then formed into stacks with pitched roofs, some thatched, and some ‘rendered’ with slurry now dried to keep out the rain. Swirls and patterns decorate this rendering, and some are even painted. These cowpats are their fuel, and very important to them. In amongst all this, and outside the houses and on the roofs, are bundles of sticks, some no more than twigs, also for fuel. Firewood is a scare commodity in this bare and scrubby area. You will see the women and children breaking branches from roadside trees. In the Ranthambore Park there are many trees, and the pickings as far as the villagers are concerned, are richer.

The Prakratic Society, started in 1999 has succeeded in setting up over 250 biogas digesters in the villages around the Ranthambore National Park. In doing so they have reduced the amount of fuel wood collected for cooking per family buy about 2.4 tonnes per annum. There are many social and health implications for the household in switching to AD plants; not having to make a round trip of some 20 km for fuel, a reduction in respiratory and eye diseases caused by smoke in the home, plus general cleanliness. From the Park’s point of view there is much less disturbance of the natural habitat, with fallen wood left to provide micro habitats, and growing trees left standing.
The digesters employed here are of the deenbandhu type, with a 3m³ body built of bricks and mortar, and the feedstock is cow dung (gobar). Households are selected on their ability to adequately service the digester, i.e. have enough cow dung to give a regular supply of gas, and in essence need 4 or more head of cattle. They have found that the fermented dung makes better fertilizer than commercial fertilizer and claim yields from farms using digestate are up by 25%.